JPH11127883A - Biological production of propane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a propane production process that can practically produce propane in an industrial scale by increasing the energy recovery in the acetone- butanol fermentation to make the energy for the recovery and separation of propane unnecessary. SOLUTION: In this biological propane production process, the fermentation raw material 1 is converted in the acetone-butanol fermentation tank 3 to 1- butanol, acetone, isopropanol, carbon dioxide, hydrogen and the like. Then, the fermentation mixture is introduced into the propane formation bioreactor 4, a NDMA (N,N'-dimethy-4-nitroso-aniline)-dependent alcohol dehydrogenase is added to the bioreactor, in addition, an aldehydecarbonylase is admixed thereto thereby producing propane from 1-butanol via butanal. The propane is evaporated from the liquid phase and stored in the gas holder 10 and liquefied with the propane liquefying apparatus 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing biological propane in which butanol produced by acetone-butanol fermentation is converted into propane by using a bioreactor in which a plurality of fermentation systems are combined and separated and recovered. It is about.

[0002]

2. Description of the Related Art Acetone-butanol fermentation is performed using starch or saccharide as a raw material, and fermentation yields 1-butanol, acetone or 2-propanol, ethanol, carbon dioxide, hydrogen, and the like. Conventionally, butanol has been used directly as gasohol or converted to isooctane for use in aircraft fuels.
Since butanol fermentation can use not only hexose but also pentose as a raw material, a method of producing biomass waste having a high hemicellulose content as a raw material is expected.

[0003] As described above, hydrogen and carbon dioxide are by-produced in acetone-butanol fermentation, and the applicant of the present invention has proposed a method of culturing petroleum-producing bacteria using these as raw materials in Japanese Patent Application No. 9-112281. This petroleum producing bacterium produces alkane / alkene, a major component of petroleum, from carbon dioxide and hydrogen under anaerobic conditions.

On the other hand, according to a report by Morikawa and Imanaka of Osaka University, a petroleum producing bacterium, which is a bacterium found in oil field soil, is an aldehyde decarbonylase that produces alkane / alkene from fatty acid via aldehyde. Has enzyme activity. This enzyme activity is found in the cell-free supernatant obtained by homogenizing the cells and centrifuging the cells, from which the purified enzyme is obtained. (Masaaki Morikawa, Tadayuki Imanaka: Petroleum production by microorganisms, -Biosynthetic pathway of aliphatic hydrocarbons-
Protein nucleic acid enzyme, Vol. 40, no. 1,52 ~
60, 1995).

[0005] According to a more recent report, when methane fermentation is carried out using methanol as a single substrate, the methanol becomes dominant by Methanosarcina barkeri, an assimilable methane-purifying bacterium. Has been found to have NDMA-dependent alcohol dehydrogenase (NDMA-ADH) enzyme activity. NDMA is N, N'-dimeth
DH is an abbreviation for yl-4-nitrosoaniline, and ADH is an abbreviation for alcohol dehydrogenase. This enzyme dehydrogenates alcohols to produce aldehydes.

For example, 1-butanol is converted to butanal as shown in the following formula (1).

[0007] This reaction proceeds in primary alcohols and benzyl alcohols.
It hardly progresses with methanol or ethanol.

[0008] NDMA-ADH has dimsutase activity, and aldehydes are converted into alcohols and fatty acids. For example, butanal is converted into 1-butanol and n-butyric acid as shown in the following formula (2). (For the above report, see Thomas Daussmannn, Alexande
r Aivasidis and Christian Wandrey.Kinetic data and
newenzymatic activities of Methanosarcinabarkerig
rown on methanol as the sole carbon source Proceed
ings of The 8th International Conference on Anaero
bic Digestion, see Volumel, 115-122, 1997)

[0009]

As described above, acetone-butanol fermentation has been conventionally known, but it is necessary to sterilize the raw material by steaming it in order to prevent the propagation of various bacteria, and to recover and separate butanol. There is a problem that the method is more difficult than methane recovery in methane fermentation.

[0010] As a conventional method for recovering and separating butanol, distillation means is employed, but energy required for distillation must be externally supplied. Recently, extraction and separation methods using octanol have been proposed to reduce the energy required for production, but the energy input to butanol production is still larger than the recoverable energy. However, acetone-butanol fermentation does not extend to methane fermentation as an energy recovery means. However, the added value of the product is characterized in that it is greater than in the case of methane fermentation.

At present, butanol is produced from petroleum, which is available at a low cost, and industrial production by acetone-butanol fermentation has not been carried out.
It is unlikely that acetone-butanol fermentation will be put to practical use except in the case where it becomes difficult to obtain petroleum or when the price of petroleum rises in the future.

[0012] On the other hand, methane fermentation is useful as an energy recovery means from organic waste, but methane is difficult to liquefy, so it is difficult to use it as a gaseous fuel at existing gas pipes or at methane production sites. It is suitable, and it is not suitable to pack methane in a cylinder like propane and transport it to a remote place.

In view of the above, the present invention has been made in view of the above, and the energy required for recovering and separating propane is not required, thereby improving the energy recovery rate of acetone-butanol fermentation. It is an object of the present invention to provide a biological propane production method that enables industrial production.

[0014]

According to the present invention, in order to achieve the above object, butanol produced by acetone-butanol fermentation is converted into butanal by dehydrogenation by adding an NDMA-dependent alcohol dehydrogenase enzyme. The present invention provides a method for producing biological propane as a basic means for producing propane from butanal by addition of another enzyme, aldehyde decarbonylase, by elimination of carbon monoxide.

As an NDMA-dependent alcohol dehydrogenase enzyme, methane fermentation is carried out using methanol as a single substrate to homogenize the bacteria in the fermentation broth in which methanol-assimilating methane-producing bacteria have become the predominant species, and centrifuged. Use cell extract, purified enzyme or immobilized purified enzyme.

[0016] The aldehyde decarbonylase enzyme is obtained by homogenizing cells from a culture solution of anaerobic petroleum-producing bacteria.
Use centrifuged cell-free extract, purified enzyme or immobilized purified enzyme.

As a specific production method, after the fermentation raw material is converted into 1-butanol, acetone, isopropanol, carbon dioxide, hydrogen, etc. in an acetone-butanol fermentation tank, the fermentation liquor flows into a propane production bioreactor, and then is subjected to NDMA. Dependent alcohol dehydrogenase enzyme, and aldehyde decarbonylase enzyme to produce propane from 1-butanol via butanal.The propane is evaporated from the liquid phase and stored in a gas holder. It is liquefied by a liquefaction device. Further, the propane-producing bioreactor has a two-stage configuration of a propane-producing first-stage bioreactor and a propane-producing second-stage bioreactor, and an NDMA-dependent alcohol dehydrogenase enzyme is added in the propane-producing first-stage bioreactor to produce propane. We propose a method to add aldehyde decarbonylase enzyme in the second stage bioreactor.

According to such a method for producing biological propane, a raw material mainly composed of hexose or pentose, such as saccharides and starches, is fed to an acetone-butanol fermentation tank in a 1- tank.
After being converted to butanol, acetone, isopropanol, carbon dioxide, hydrogen, etc., it flows into a propane production bioreactor, and an NDMA-dependent alcohol dehydrogenase enzyme is added as an enzyme active solution, a purified enzyme or an immobilized enzyme, and furthermore, an aldehyde decal. Propane is produced from 1-butanol via butanal by adding a bonylase enzyme as an enzyme activity solution, a purified enzyme or an immobilized enzyme.

This propane is vaporized from the liquid phase and stored in a gas holder, and then liquefied by a propane liquefier.
The remaining carbon monoxide is introduced into the combustion treatment or methane fermentation tank by carbon monoxide treatment means, and by-products such as acetone, isopropanol, and ethanol are separated into solid and liquid by a solid-liquid separation device. The liquid portion is returned to the propane-producing bioreactor via the return / discharge means, and the liquid portion is purified by a fractional distillation apparatus to unreacted 1-propanol, acetone, isopropanol, ethanol, and the like.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the method for producing biological propane according to the present invention will be described. In the first embodiment of the present invention, hexose or pentose is used as a raw material, butanol produced by acetone-butanol fermentation is not separated from the fermentation solution, but is converted to propane via butanol using two enzymes. There is a way to do it.

One of the above two enzymes is NDM
A-dependent alcohol dehydrogenase (NDMA-AD
H), which is a methanol-utilizing methane-producing bacterium by performing methane fermentation using methanol as a single substrate.
Methanosarcina barkeri is contained in the fermented broth that has become the dominant species. The supernatant (cell-free extract) obtained by homogenizing and centrifuging the bacteria in the fermentation solution is used as an NDMA-ADH enzyme activity solution.

When this enzyme activity solution is added to the acetone-butanol fermentation solution, 1-butanol is dehydrogenated according to the above formula (1) and converted to butanal. Thereafter, by adding another enzyme, aldehyde decarbonylase, carbon monoxide is eliminated from butanal as shown in the following formula (3) to produce propane. Aldehyde decarbonylase is also contained in the supernatant (cell-free extract) obtained by homogenizing the cells from the culture of anaerobic petroleum-producing bacteria, and then obtaining the purified enzyme from this liquid. . Cell-free extracts, purified enzymes or more preferably immobilized purified enzymes are used.

FIG. 1 is a schematic diagram of an apparatus system for executing the first embodiment. First, the configuration of the apparatus will be described. 1 is a raw material for acetone-butanol fermentation, 2 is a hydrolysis apparatus, 3 is an acetone-butanol fermentation tank, 4 is a propane production bioreactor, 5 is a stirring mechanism, and 6 is NDM.
A-ADH supply means, 7 is a methane fermentation tank using methanol as a single substrate, 8 is an aldehyde decarbonylase supply means, 9 is an anaerobic petroleum producing bacteria culture tank, 10 is a gas holder, 11 is a propane liquefaction apparatus, and 12 is A carbon monoxide treatment unit, 13 is a solid-liquid separation unit, 14 is a solid return / discharge unit, 15 is a fractional distillation unit, and 16 is a waste liquid treatment unit.

As a raw material 1 for the acetone-butanol fermentation, a hexose such as a saccharide or a starch or a pentose is used as a main component. In addition, cellulose or hemicellulose was used as raw material 1
In this case, the hydrolysis device 2 is required.

The raw material 1 is converted in the acetone-butanol fermentation tank 3 into 1-butanol, acetone, isopropanol, carbon dioxide, hydrogen and the like. The fermentation liquor discharged from the acetone-butanol fermentation tank 3 flows into the propane production bioreactor 4, and the NDMA-ADH supply means 6 supplies the NDMA-ADH enzyme as an enzyme active solution, a purified enzyme or an immobilized enzyme. Further, the aldehyde decarbonylase enzyme is supplied from the aldehyde decarbonylase supply means 8 as an enzyme active solution, a purified enzyme or an immobilized enzyme, and the reaction is promoted by the stirring means 5 to produce propane.

The NDMA-ADH supply means 6 is supplied with a supernatant (cell-free extract) obtained by homogenizing and centrifuging a fermentation solution discharged from a methane fermentation tank 7 using methanol as a single substrate. The aldehyde decarbonylase supply means 8 is supplied with a supernatant (cell-free extract) obtained by homogenizing and centrifuging a fermentation solution discharged using carbon dioxide and hydrogen as substrates in an anaerobic petroleum producing bacteria culture tank 9. ing. Incidentally, means for purifying the enzyme to obtain an immobilized enzyme is also included.

In the propane producing bioreactor 4
-Propane generated from butanol via butanal is volatilized from the liquid phase and stored in the gas holder 10.
This propane is liquefied by a propane liquefaction unit 11,
The remaining carbon monoxide is burned by the carbon monoxide treatment means 12 or introduced into a methane fermentation tank (not shown), or is converted into carbon dioxide and hydrogen by steam conversion and sent to the anaerobic petroleum producing bacteria culturing tank 9, where It can be used as a raw material for producing bacteria culture.

Since acetone, isopropanol, ethanol, and the like, which are by-products of the acetone-butanol fermentation, do not change in the propane-producing bioreactor 4, they are separated into a solid and a liquid by the solid-liquid separator 13, and the solid portion is returned and discharged as a solid. It is returned to the propane production bioreactor 4 via the means 14, and the excess solid is discharged out of the system. The unreacted 1-propanol, acetone, isopropanol, ethanol or the like is purified from the liquid portion by the fractional distillation device 15 or the waste liquid is treated by the waste liquid treatment device 16.

FIG. 2 is a schematic diagram of an apparatus system for executing the second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals. .

To explain the structure of the apparatus, 1 is acetone-
Raw materials for butanol fermentation, 2 is a hydrolysis device, 3 is an acetone-butanol fermentation tank, 4A is a propane production first-stage bioreactor, 5A is a stirring mechanism, and 6 is NDMA-AD.
H supply means, 7 is a methane fermentation tank using methanol as a single substrate, 13A is a solid-liquid separator, 14A is a solid return / discharge means, 4B is a propane production second stage bioreactor, 5B
B is a stirring mechanism, 8 is an aldehyde decarbonylase supply means, 9 is an anaerobic petroleum producing bacteria culture tank, 10 is a gas holder, 11 is a propane liquefaction apparatus, 12 is a carbon monoxide treatment means, 13B is a solid-liquid separation apparatus, 14B Is a solid return discharge means, 15 is a fractional distillation apparatus, and 16 is a waste liquid treatment apparatus.

According to the second embodiment, the raw material 1 is 1-butanol,
It is converted to acetone, isopropanol, carbon dioxide, hydrogen, etc. The fermentation liquor discharged from the acetone-butanol fermentation tank 3 flows into the propane production first-stage bioreactor 4A, and is supplied from the NDMA-ADH supply means 6 to the N-ADH supply means 6.
The DMA-ADH enzyme is supplied as an enzymatically active solution, a purified enzyme or an immobilized enzyme. The reaction is promoted by the stirring means 5A, and the inflowing acetone-butanol fermentation solution is changed into 1-butanol as a main component to produce propane. The liquid part flows out of the first-stage bioreactor 4A, flows into the propane-producing second-stage bioreactor 4B, the solid part is separated into solid and liquid by the solid-liquid separator 13A, and part of the solid part is returned and discharged. The propane is returned to the first stage bioreactor 4A via the means 14A, and the excess solid is discharged out of the system.

The NDMA-ADH supply means 6 includes:
A supernatant (cell-free extract) obtained by homogenizing and centrifuging a fermentation solution discharged from the methane fermentation tank 7 using methanol as a single substrate is supplied.

On the other hand, the aldehyde decarbonylase enzyme is supplied from the aldehyde decarbonylase supply means 8 to the liquid part flowing into the propane-producing second-stage bioreactor 4B as an enzyme active solution, a purified enzyme or an immobilized enzyme. The reaction is promoted by the means 5B, and the butanal in the liquid is changed to propane by the action of the aldehyde decarbonylase enzyme.

The aldehyde decarbonylase supply means 8 is supplied to the anaerobic petroleum-producing bacteria culturing tank 9 with a supernatant liquid (cell-free extraction) obtained by homogenizing and centrifuging a fermentation liquid discharged using carbon dioxide and hydrogen as substrates. Liquid) is being supplied. Incidentally, means for purifying the enzyme to obtain an immobilized enzyme is also included.

Propane Production Propane produced in the second-stage bioreactor 4B is volatilized from the liquid phase to form a gas holder 1
Stored at 0. This propane is a propane liquefier 11
The remaining carbon monoxide, which is liquefied by carbon dioxide, is burned by a carbon monoxide treatment means 12 or introduced into a methane fermentation tank (not shown), or converted into steam and carbon dioxide and hydrogen by anaerobic petroleum production cultivation tank 9. Sent to
It can be used as a raw material for culturing petroleum-producing bacteria.

Acetone, isopropanol, ethanol, and the like, which are by-products of the acetone-butanol fermentation, do not change in the propane-producing second-stage bioreactor 4B, and are separated into a solid and a liquid by the solid-liquid separator 13B.
The solid portion is returned to the propane production second stage bioreactor 4B via the solid return and discharge means 14B, and excess solid is discharged out of the system. The unreacted 1-propanol, acetone, isopropanol, ethanol or the like is purified from the liquid portion by the fractional distillation device 15 or the waste liquid is treated by the waste liquid treatment device 16.

The propane obtained in the present embodiment is a gas at normal temperature and has low solubility in water, so that it can be easily separated from the fermentation broth. Moreover, since propane is easily liquefied, it can be used after being packed in a cylinder and transported to a remote place.

The energy required for recovering and separating propane is almost unnecessary, and is characterized in that the energy recovery rate of acetone-butanol fermentation is improved.

[0039]

As described above in detail, the biological propane production method according to the present invention differs from the conventional distillation means for recovering and separating butanol by utilizing the acetone-butanol fermentation. There is no need to input the energy required for distillation from the outside, and the situation that the energy input to butanol production is larger than the recoverable energy is eliminated, and the raw materials are steamed to prevent the propagation of various bacteria. A propane production method is provided in which complicated steps such as sterilization are not required, and the added value of the product is greater than that of methane fermentation.

Although methane fermentation is useful as a means of recovering energy from organic waste, it is unsuitable to pack methane in a cylinder like propane and transport it to a remote location. In the case of the present invention, by improving the energy recovery rate of the acetone-butanol fermentation, biological liquefaction of propane that is easy to liquefy and can be used in remote places by packing in a cylinder is available. A method can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an apparatus system according to a first embodiment of the present invention.

FIG. 2 is an apparatus system schematic diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Raw material (of acetone-butanol fermentation) 2 ... Hydrolysis apparatus 3 ... Acetone-butanol fermentation tank 4 ... Propane production bioreactor 4A ... Propane production first stage bioreactor 4B ... Propane production second stage bioreactor 5, 5A, 5B: stirring mechanism 6: NDMA-ADH supply means 7 ... methane fermentation tank (using methanol as a single substrate) 8 ... aldehyde decarbonylase supply means 9 ... anaerobic petroleum producing bacteria culture tank 10 ... gas holder 11 ... propane liquefaction apparatus 12 ... carbon monoxide treatment means 13, 13A, 13B ... solid-liquid separation device 14, 14A, 14B ... solid return and discharge means 15 ... fractional distillation device 16 ... waste liquid treatment device

Claims (5)

[Claims] 1. An NDMA-dependent alcohol dehydrogenase enzyme is added to butanol produced by acetone-butanol fermentation to convert it into butanal by dehydrogenation, and further another enzyme, aldehyde decarbonylase, is added to the mixture to form a monooxide. A method for producing biological propane, comprising producing propane from butanal by carbon elimination. 2. The method according to claim 1, wherein the NDMA-dependent alcohol dehydrogenase enzyme is subjected to methane fermentation using methanol as a single substrate to homogenize the bacteria in the fermentation broth in which the methanol-utilizing methane-producing bacteria have become the dominant species, and centrifuge. 2. The method for producing biological propane according to claim 1, wherein the separated cell-free extract, purified enzyme or immobilized purified enzyme is used. 3. The aldehyde decarbonylase enzyme is characterized by using a cell-free extract, purified enzyme or immobilized purified enzyme obtained by homogenizing cells from a culture solution of anaerobic petroleum-producing bacteria and then centrifuging the cells. Claim 1
A method for producing biological propane as described. 4. A fermentation raw material is treated in an acetone-butanol fermentation tank with 1-butanol, acetone, isopropanol,
After conversion to carbon dioxide, hydrogen, etc., the fermentation liquor flows into the propane production bioreactor, then adds NDMA-dependent alcohol dehydrogenase enzyme, and further adds aldehyde decarbonylase enzyme, via 1-butanol to butanal To produce propane, the propane is volatilized from the liquid phase and stored in a gas holder,
4. The method for producing biological propane according to claim 1, wherein the liquid is liquefied by a propane liquefier. 5. A fermentation raw material is prepared in an acetone-butanol fermentation tank by using 1-butanol, acetone, isopropanol,
After being converted to carbon dioxide, hydrogen, etc., the fermentation liquor flows into the propane production first-stage bioreactor and the NDMA-dependent alcohol dehydrogenase enzyme is added. Producing propane from 1-butanol via butanal by adding a decarbonylase enzyme;
The method according to claim 1, 2, or 3, wherein the propane is vaporized from a liquid phase, stored in a gas holder, and then liquefied by a propane liquefier.